1. Field of the Invention
The present invention relates to a method of executing a plurality of steps that are performed sequentially in temporal order under computer control.
2. Background
The design of molds used in the injection molding of plastic and molds used in the casting of cast parts had previously required skilled work in determining the shape of the cavity used to form the mold from the design drawings for the product, and in providing slide cores and loose cores for undercut areas and opening areas. Recently, with the appearance of three-dimensional CAD, it is possible to obtain product design values as 3D digital data. If the product design values are obtained as 3D digital data, it is possible to determine the shapes of mold cavities from that 3D digital data, thereby greatly simplifying mold design. However, even if mold design is performed using 3D digital data, the current situation is such that many items that require the work of skilled workers still remain, including the design of slide cores and loose cores to handle complex product shapes.
One proposal is to divide the design work process into a plurality of steps and assign each step by specialty to a different worker, but with such a division of labor, it takes time and effort to pass work along, so it is difficult to reduce the number of days required for design. In addition, even after the design of the mold is completed, there is no guarantee that the work of preparing numerical control data (NC data) for the fabrication of molds based on the design data, and the work of machining the molds will be performed efficiently and without delay. Accordingly, the design and fabrication of molds was a problem that required a large amount of time extending to several months.
In addition, not restricting ourselves to the design and fabrication of molds, when any work consisting of a plurality of steps is performed consecutively in a specific order, the establishment of coordination among the various steps is necessary for the work to be performed efficiently.
The present invention was accomplished in light of the aforementioned circumstances and has as its fundamental object to provide a method whereby, when work consisting of a plurality of steps is performed sequentially, that work can be performed efficiently under computer control.
Another object of the present invention is to provide a method of designing and fabricating molds that can be performed easily without particular reliance on skilled workers.
In order to achieve the aforementioned objects, the present invention provides a method whereby work consisting of a plurality of steps performed sequentially is executed under computer control. This method uses a central processing computer and a plurality of terminal computers, where each of the plurality of steps is executed by one of the respective terminal computers. Moreover, when one terminal computer assigned to a single step has completed the work in the step assigned to it and is able to execute the work in the next step, that one terminal computer sends a work completion signal to the central processing computer. The central processing computer receives this work completion signal and prepares a work item notice that indicates that it is possible to start the next step that is to be performed next after this one step such that it can be displayed on the screen of the terminal computer used for the next step which is to be assigned to the next step. The terminal computer used for the next step allows the work item notice displayed on its display screen to be clicked to start work on the next step assigned to it.
In the event that one step among the plurality of steps includes a plurality of tasks that can be performed in parallel, the central processing computer recognizes from the steps prior to this one step that this one step contains a plurality of tasks that can be performed in parallel, and when a work completion signal arrives from the terminal computer assigned to the step immediately prior to this one step, it can generate a number of work item notices corresponding to the plurality of tasks.
In one preferred embodiment, the present invention provides a method of performing the design and fabrication of molds using a central processing computer that stores three-dimensional digital data that represents the product shape, and a plurality of computer terminal units connected to this central processing computer via communication lines. This method comprises: a step of calling up three-dimensional digital data describing the product shape from said central processing computer to a first computer terminal unit, performing a three-dimensional display of the product shape on the screen of said first computer terminal unit, determining a partition line between the upper and lower mold halves based on said screen display, confirming the partition surface between the upper and lower mold halves along said partition line and the mold formation surface shapes of the upper and lower mold halves, respectively, and sending same to said central processing computer where it is saved as digital data, a step of calling up three-dimensional digital data describing the product shape including the digital data formed in said first computer terminal unit from said central processing computer to a second computer terminal unit, performing a three-dimensional display of the product shape on the screen of said second computer terminal unit, determining the locations where slide cores are necessary and the slide direction, and, based on the size of the slide cores needed at the various locations, selecting ones from among a plurality of standard core blocks of different sizes and shapes that are prepared in advance and thus determining the slide core block to be used, placing this slide core block on the outside of the molding surface in said slide direction, and when the slide block is placed, drawing slide pockets required for the sliding of said slide block in the upper and lower mold halves, respectively, providing slide cores of a shape determined based on the shape of the molding surface at the tip in the slide direction of the slide core, and sending same to said central processing computer where it is saved as digital data, a step of calling up three-dimensional digital data describing the product shape including the digital data formed in said second computer terminal unit from said central processing computer to a third computer terminal unit, performing a three-dimensional display of the product shape on the screen of said third computer terminal unit, determining the locations where a loose core is necessary, and, based on the size of the loose cores needed at the various locations, selecting ones from among a plurality of standard core blanks of different sizes and shapes that are prepared in advance and thus determining the core blank to be used, placing this core blank at the stipulated position on the molding surface, determining the shape of the tip of the loose core based on shape data for the molding surface, and sending same to said central processing computer where it is saved as digital data, a step of calling up three-dimensional digital data describing the product shape including the digital data formed in said third computer terminal unit from said central processing computer to a fourth computer terminal unit, performing a three-dimensional display of the product shape on the screen of said fourth computer terminal unit, determining the locations of ejector pins, determining the length of the ejector pins from the ejector pin locations and the molding surface shape, and sending same to said central processing computer where it is saved as digital data, a step of calling up the various data determined above from said central processing computer, preparing numerical control data for mold fabrication based on said data, and sending said numerical control data to said central processing computer where it is saved, and a step of getting said numerical control data from said central processing computer and fabricating a mold.
In another preferred embodiment, the present invention provides a method of performing the design and fabrication of molds using a central processing computer that stores three-dimensional digital data that represents the product shape, and a plurality of computer terminal units connected to this central processing computer via communication lines. This method comprises: a step of calling up three-dimensional digital data describing the product shape from said central processing computer to a first computer terminal unit, performing a three-dimensional display of the product shape on the screen of said first computer terminal unit, determining a partition line between the upper and lower mold halves based on said screen display, confirming the partition surface between the upper and lower mold halves along said partition line and the mold formation surface shapes of the upper and lower mold halves, respectively, and sending same to said central processing computer where it is saved as digital data, a step of calling up three-dimensional digital data describing the product shape including the digital data formed in said first computer terminal unit from said central processing computer to a second computer terminal unit, performing a three-dimensional display of the product shape on the screen of said second computer terminal unit, determining the locations where insert cores are necessary, and, based on the size of the insert cores needed at the various locations, selecting ones from among a plurality of standard core blocks of different sizes and shapes that are prepared in advance, providing insert cores of the size and shape required, and sending same to said central processing computer where it is saved as digital data, a step of calling up three-dimensional digital data describing the product shape including the digital data formed in said second computer terminal unit from said central processing computer to a third computer terminal unit, performing a three-dimensional display of the product shape on the screen of said third computer terminal unit, determining the locations of ejector pins, determining the length of the ejector pins from the ejector pin locations and the molding surface shape, and sending same to said central processing computer where it is saved as digital data, a step of calling up the various data determined above from said central processing computer, preparing numerical control data for mold fabrication based on said data, and sending said numerical control data to said central processing computer where it is saved, and a step of getting said numerical control data from said central processing computer and fabricating a mold. In this case, an insert core may be a slide core or loose core.
In the method according to this preferred embodiment, each of the computer terminal units may send work completion signals to the central processing computer when the step assigned to it is completed, and upon receiving a completion signal for each step, the central processing computer may prepare a work item notice that indicates that it is possible to start the next step that is to be performed next after this one step such that it can be displayed on the screen of the terminal computer which is to be assigned to the next step. The terminal computer assigned to the next step may allow the displayed work item notice to be clicked to start work on the next step assigned to it. The step of forming digital data for cores may include the work of preparing digital data for a plurality of cores, and the central processing computer may be able to display a number of work item notices corresponding to the number of cores on the same number of computer terminal units.
The step of preparing numerical control data may include the tasks of preparing digital data for a plurality of parts, and the central processing computer may be able to display a number of work item notices corresponding to the number of tasks on the same number of computer terminal units.
In the present invention, a step of calling up three-dimensional digital data describing the product shape from said central processing computer to a computer terminal unit, performing a three-dimensional display of the product shape on the screen of said first computer terminal unit, using an exposure device to expose ultraviolet curing resin based on said three-dimensional digital data to create a stereolithographic model as a model of the product, and if the product consists of two or more parts that are assembled, using this stereolithographic model to confirm that there is no problem with it in the assembled state is performed prior to the step performed by said first computer.
In still another preferred embodiment, the present invention provides an apparatus whereby work consisting of a plurality of steps performed sequentially is executed under computer control, comprising: a central processing computer and a plurality of terminal computers, each of which executes one of said plurality of steps, wherein: when one of said terminal computers assigned to a single step has completed the work in the step assigned to it and is able to execute the work in the next step, that one terminal computer transmits a work completion signal, said central processing computer receives this work completion signal and prepares a work item notice that indicates that it is possible to start the next step that is to be performed next after this one step such that it can be displayed on the screen of the terminal computer used for said next step which is to be assigned to the next step, and said terminal computer used for the next step allows the work item notice displayed on its display screen to be clicked to start work on said next step assigned to it.
In still another embodiment, the present invention provides a manufacturing process control apparatus that controls a manufacturing process divided into a plurality of steps that are controlled by a plurality of user terminals, comprising: transmitting means that, when conditions for the execution of one step of said plurality of steps are met, transmits to the user terminal that controls said one step information (a signal) to the effect that said step can be started, and receiving means that, when said one step of the plurality of steps is complete, receives from the user terminal that controls said one step information (a signal) to the effect that said one step is complete.
Here, the control of steps is defined to include when the user terminal itself executes the work contained within a step, along with when work contained within that step is performed by other equipment connected to the user terminal.
Moreover, xe2x80x9cwhen conditions for the execution of one step are metxe2x80x9d means when the data required to execute the work contained in that step and other information is all present and usable.
This apparatus preferably further comprises: a first storage means that stores information required to execute said plurality of steps, wherein: based on information stored in said first storage means, said transmitting means determines whether or not the conditions for the execution of one step of said plurality of steps are met. In addition, when the conditions for the execution of one step are met, said transmitting means transmits to the user terminal to execute said one step information required for the execution of said one step. Moreover, when one step is complete, said receiving means receives from the user terminal that executed said one step the information generated in said one step, and stores said information in said first storage means.
Moreover, the apparatus preferably comprises: a second storage means that stores information to the effect that one step is complete that is received by said receiving means, and progress control means that controls the progress of the manufacturing process based on the information stored in said second storage means.
In still another embodiment, the present invention provides a manufacturing process control method for controlling a manufacturing process divided into a plurality of steps that are controlled by a plurality of user terminals, comprising: a transmitting step whereby, when conditions for the execution of one step of said plurality of steps are met, information (a signal) to the effect that said step can be started is transmitted to the user terminal that controls said one step, and a receiving step whereby, when said one step of the plurality of steps is complete, information (a signal) to the effect that said one step is complete is received from the user terminal that controls said one step.